Apparatus for the control of internal combustion engines



April 18, 1944. F. B. HALFOVRD EI'AL 5,

APPARATUS FOR THE CONTROL OF INTERNAL.COMBUSTION ENGINEEI Filed May 12 1942 Patented Apr. 18, 1944 Frank Bernard Halford, Edgware, and Adrian Leslie Cattord, Hampton, England, assignors to D...Napier & Son Limited, London, England, a company of Great Britain Application May 12, 1942, Serial No. 442,676

In Great Britain July 1'1, 1941 6 Claims. (Cl. 170-1351;)

' This invention relates to apparatus for the control of internal combustion engines as used for the propulsion of aircraft and has for its object to effect certain improvements in control mechanism of the type in which by movement of a single hand lever there is effected adjustment of the throttle and of the air screw governor while it is also possible for an adjustment of the throttle to be efiected by variations inthe pressure existent in the induction system of the engine, this pressure being commonly referred to as the boost pressure.

According to this invention there is combined as it is moved to move the throttle and act on the airscrew governor.

The slotted links and the pin or the like, constituting the interconnection between these links with a servo controlled by boost pressure, mechanism provided with a hand lever for actuating it whereby both the engine throttle and the airscrew governor can be controlled simultaneously, and an interconnection between this mechanism and the servo comprising a. pin or like member connected 'to the engine throttle and engaging two slotted links mounted and swinging as levers to which movement is respectively imparted by the hand control lever and by the servo. The two slotted links lie adjacent and cross each other at an angle with the pin engaging them both and the positionvof this pin with respect to the fulcrum about which can swing the one leverlink, and thus the movement that can be imparted to the pin by that lever-link, is deter-, vmined by the positioning of the second lever-link.

By means of the connection between the interconnecting pin and the engine throttle movement can lie imparted to the throttle from each leverlink independently, the first lever-link being swung by movement of the hand control lever which then also controls the airscrew governor, and the servo which is controlled by boost pressure acts on and moves the second lever-link. Conveniently there is a two-armed lever of which one arm carries the one slotted link while a second lever carries the other slotted link which lies adjacent to and across the first link. There is a suitable connection between the hand control lever and the first link-carrying lever and also to the airscrew governor so that the latter will be adjusted simultaneously with movement of the throttle by the hand lever. The second lever with its link is swung by the action of the servo and the latter can thus move the throttle through can be set and varied by the hand control lever and their respective levers and the throttle, are so constructed and arranged that the hand control lever can be rendered inoperative on the throttle by the servo acting as determined by the boost pressure on the interconnecting pin. This is efiiected by the servo-actuated link moving the pin, into a position in the first link where it is substantially coincident with the fulcrum about which the first link-lever is' swung by the hand control lever. Movement of the latter then will have no effect on the throttle, but the hand lever can continue to act on the airscrew governor and can also eflfect setting of the boost datum. However, should a rise in boost pressure occur the servo will move the throttle-actuating pin into a position in the first link where it again becomes possible for movement to be given to the throttle by the hand lever. The construction and arrangement of the slotted links and the This setting of the boost datum is conveniently.

effected by a cam which acts on the capsule as the hand lever is moved.

It will thus be apparent that the levers carrying the slotted links permit the throttle to be.

altered independently by the hand lever and by the servo whether these levers are respectively moved at the same time or separately.

The accompanying drawing illustrates diagrammatically and partly in section mechanism such as may be employed byway of example in carrying the invention into practice.

In a servo cylinder A is a piston B whose movements in the cylinder are efiected by liquid such as oil under pressure passing to and from the cylinder through the passages A and A The flow through these passages of the liquid which is supplied through a passage C and can drain away through passages C is controlled by the movements of a valve D connected to one end of an evacuated capsule E whose other end is held against movement. Theposition of this fixed end, however, can be adjusted for instance by movement of a cam F which is pivoted at F and bears on the end of a projection E from the one end of the capsule, but this adjustment which determines the boost pressure datum for the operation of the capsule, may be effected in some position of the servo piston B and the parts to which it is connected or on which it can act.

By means of a hand control lever K acting through links L, L adjustment of the cam F and the datum of the capsule E can be effected, such adjustment and the general arrangementand operation of the boost servo as described above being on known lines. By suitable linkage or other mechanism movement can be imparted from the hand lever K to a slotted link M which can swing about 'a centre M the link forming or being carried by one arm of a two-armed lever to the other arm W of which the hand lever is connected for example as shown by the link L,

bell-crank lever L, link L bell-crank lever L and link L Through this last link, or otherwise as may be convenient, the hand lever can act on and adjust the air screw governor N. Thus movement of the hand lever K will simultaneously swing the slotted link M, adjust the datum of the boost servo B and also adjust the airscrew governor.

The servo piston B is connected as by way of a rod B and link B with a lever 0 pivoted at O to some fixed part. This lever carries a slotted link 0 which lies adjacent and across and thus at an angle to the slotted link M. A pin or the like P engages and can slide in the slots in both the links M and O which are in this way interconnected. It will be noted that the slot in the swinging lever-link M extends irom its free end to at least the axis M about which that lever canswing so that the pin P can be moved into a position wherein its axis will coincide, or substantially coincide with the fulcrum axis of the lever-link. The positioning of the pin P in the slotted link M will be effected by the lever-link O, 0 whose movements are determined by the servo B as controlled by boostpressure acting on the capsule M. The pin P is connected to the throttle J as for instance by a link Q, bell-crank lever Q and link Q Thus by this or other suitable mechanism the throttle can be moved by the independent action of the hand control lever K or by the servo B. The throttle movement by the hand lever will take place as the lever-link M is swung and the extent of the throttle movement will be determined by the position of the pin P along the slot in the link M, but it will be noted that no movement can be transmitted to the throttle from the hand lever if the pin P happens to have been positioned in the one end part of the slot where it lies coincident,with the fulcrum axis of the lever M, MK The throttle movement by the servo piston B will-result from swinging of the leverlink 0, O as this slides the pin Palong in the slot in the link M and positions it in the slot. The pin P will be held by the lever-link O, O in the position in the slotted link M into which it has been moved while the lever-link M, M is swung.

other convenient manner. The capsule E is dis not transmit any movement to the cam F or to the airscrew governor which are controlled by the hand lever K. It is to be noted also that movements oi the throttle by the servo B will be determined by the setting of the throttle that has been efiected by thehand lever and by the relative angular positions of the slot in the link M and the slot in the link 0- at the time when the lever-link O, O is moved by the servo. Yet further it will be seen that whatever the datum setting oi the boost pressure capsule E by the hand lever K the action of the servo alone on the pin P can cause full throttle opening.

The .formation, disposition and proportions of the swinging lever-links M, M and O, O and the shape and arrangement of the slots in these links may vary as found desirable. may be straight while that part of the lever in which the slot is formed may lie at an angle with another part of that lever. Alternatively the slot in one or in each lever-link may be curved.

The extent of movement given to the throttle by movement of the hand lever K will be dependent on the position of the pin P in the slot in the link M, as determined by the action of the servo B acting through the lever-link O, O, or as mentioned the hand lever may be prevented from moving the throttle at all if the pin P has been positioned in the slotted link M where it will coincide with the axis about which that link is swung. On the other hand, as indicated above, the angular setting of the link'M can affect the extent of movement imparted to the throttle by the servo B acting alone.

What we claim as ourinvention and desire to secure by Letters Patent is:

1. In apparatus for the control of an internal combustion engine as used for the propulsion of aircraft including an engine having a throttle and an air screw pitch governor, the combination of two links each mounted and swinging as a lever and lying adjacent and crossing each other at an angle, a member engaging and sliding along both links, the position'of said member along one of said links being determined by swinging movement 01' the other link, a connection between said sliding member and the engine throttle, a hand lever and means whereby it can swing one of said first links and simultaneously control the air screw pitch governor, and a servomotor which is controlled by boost pressure and is operative to move the said second link.

2. In apparatus for the control of an internal combustion engine as used for the propulsion of aircraft including an engine having a throttle and an air screw pitch governor, the combination of two links each mounted and swinging as a lever and lying adjacent and crossing each other at an angle, a member engaging and sliding along both links, the position of said member along the one link being determined by swinging movement of the second link, a connection between said sliding member and the engine throttle, a hand lever, and means whereby it can swing said first link and simultaneously control said air screw pitch governor, a capsule and servomotor actuated by the eflect of boost pressure on said capsule, said servomotor being operative to move said second link, and means whereby movement of the said hand lever will act on said capsule and effect an alteration of its datum.

3. In apparatus for the control of an internal combustion engine as used for the propulsion of aircraft including an engine having a throttle and an air screw pitch governor, the combination Each slot itself.

of a first lever one arm of which carries a slotted link, a second lever carrying a slotted link adjacent to and crossing at an angle the slotted link of said first lever, a hand control lever, means whereby the first lever and its link can be swun by movement of said hand lever, means for simultaneously acting on the air screw pitch governor, a servomotor means for controlling said motor byboost pressure, means whereby said servomotor can swing said second lever and its link, a pin engaging and sliding in both of said slotted links and forming an interconnection between their respective levers, a connection between said pin and said engine throttle, the position of said pin along said first slotted link being determined by the swinging movement of said second link,'movement of each 1ink-carryinglever being capable of imparting movement to the engine throttle independentlyof the other linkcarrying lever.

4. In apparatus as specified in claim 3 wherein the slot in the link forming one arm of said bell crank lever extends at least to the fulcrum axis about which said lever swings whereby the pin which engages said slot can be moved in it by the swinging of said second lever link with which this pin is also in engagement into a position wherein the axis of the pin and the fulcrum axis of said two-armed lever substantially coincide whereupon said hand leverwill be inoperative to transmit movement to the throttle.

5. In apparatus for the control of an internal ,combustion engine as used for the propulsion of aircraft including an engine having a throttle and an air screw pitch governor, the combination of two links each mounted and swinging as a lever and lying adjacent and crossing each other at an angle, a member engaging and sliding along both links, the position of said member along the one link being determined by the swinging movement of the second link, a connection between said sliding member and said engine throttle, a hand lever, means whereby said lever can swingsaid first lever link and simultaneously control the air screw pitch governor, a servomotor operative to move said second link, a valve controlling said servomotor, and a capsule subject to the effect of, boost pressure in the induction passage to said engine and actuating the valve of the servomotor.

6. In apparatus as specified in claim 5, including means for setting and varying the operating datum of the said capsule, and means whereby this variation will be effected by said hand lever as it is moved.

FRANK BERNARD HAL-FORD. ADRIAN LESLIE CATFORD. 

